| 摘要 |
<p>The flask lid has a central part (1) joined to a skirt (2) which fits tightly inside the neck of the flask. The flask has an external thread (3) and the outside of the lid (13) is cylindrical externally and has an internal thread. A skirt extension (5) fits over the shoulder (9) on the flask. The shoulder has a rib (8), and the lid has a tongue (6) to prevent unscrewing without breaking the tongue. The rib has a sloping side to allow screwing on of the lid, and a flat side to prevent unscrewing.</p> |
